Switches are an important class of semiconductor devices. Many types of such devices have been devised which are capable of switching either electronic or optical signals. A single device capable of simultaneously switching both optical and electrical signals and useful in optical logic circuit would be desirable.
Switching of optical signals is desirable in optical communications and integrated opto-electronic circuits. Devices capable of, for example, steering and modulating optical signals have been developed. For example, lithium niobate waveguides and the quantum well self electro-optic effect device (SEED) have been developed. However, the optical gain of these devices is less than unity and the input control signal is electrical.
A recently developed solid state device, termed a BICFET, (which is an acronym for Bipolar Inversion Channel Field Effect Transistor) has recently been developed, and is described in copending application Ser. No. 653,440, now abandoned, assigned to a common assignee and incorporated herein by reference. In one embodiment, this device comprises a metallic emitter contacting a wider bandgap region; a narrow bandgap collector region; and a channel contact. The latter is to an inversion layer which is formed at the interface between the wider bandgap region and the narower bandgap region. Further embodiments enable the BICFET to function as either a photodetector or a light emitter. However, simultaneous switching of both types of signals was not described.